Nutty Lemon Blueberry Coffee Cake (Gluten-Free)

This recipe comes to us from Chris Spreitzer.

1 cup softened butter or margarine
1 cup sugar
3 eggs
1 cup sour cream
1 teaspoon gluten-free vanilla extract
zest of two medium lemons
juice of one lemon
2 ½ cups gluten-free flour mix
1 ¼ teaspoon xanthan gum
2 ½ teaspoon baking powder
1 teaspoon baking soda
1/8 teaspoon salt
2 cups fresh blueberries

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Topping:

1 cup chopped pecans
½ cup sugar
1 teaspoon cinnamon

Cream together butter and sugar. Add eggs, one at a time, mixing well after each addition. In another bowl, mix sour cream, vanilla, lemon zest and lemon juice. Combine gluten-free flour mix, xanthan gum, baking powder, soda, and salt. Alternately add flour mixture and sour cream mixture to creamed mixture, about a third of each at a time. Stir in blueberries. Dough will be fairly stiff. Spread half in a greased 9x13x2 glass baking pan. Combine topping ingredients, sprinkle half of topping mixture over dough. Carefully spread remaining dough on top of topping. Sprinkle with remainder of topping. Bake at 350 for 35-40 minutes or until cake tests done. Yield 16-20 servings.